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Publication numberUS4429341 A
Publication typeGrant
Application numberUS 06/260,871
Publication dateJan 31, 1984
Filing dateMay 6, 1981
Priority dateMay 6, 1981
Fee statusLapsed
Publication number06260871, 260871, US 4429341 A, US 4429341A, US-A-4429341, US4429341 A, US4429341A
InventorsCharles H. King
Original AssigneeThe Boeing Company
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Lightning protection for external surface composite material of an aircraft
US 4429341 A
Abstract
An ordinary lightning-accessible surface of an aircraft component consisting of a composite material such as a graphite epoxy composite includes one or more layers of dielectric material applied over the exposed composite surface portion of the aircraft, the outermost layer of dielectric material having a binder on the exposed surface thereof for holding a finely divided metal powder distributed uniformly over the surface of the outermost layer of dielectric material.
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Claims(1)
What is claimed is:
1. A lightning diverter structure for an aircraft external surface portion of composite material comprising in combination therewith:
a layer of dielectric material having a lower surface adapted to be applied to the aircraft external surface portion of composite material, said layer of dielectric material having an upper surface comprising a major surface area opposite said lower surface;
a binder on said upper surface containing a conductive metal power of finely divided metallic particles deposited in said binder and uniformly extending over said upper surface;
an aircraft structural component comprising a metal support member for supporting said aircraft external surface portion of composite material and providing reference potential; and
said layer of dielectric material having a thickness of between 0.01 inches and 0.1 inches, said thickness of said layer of dielectric material being greater with increasing distance of said dielectric layer from said metal support member providing said reference potential.
Description

The present invention relates generally to aircraft lightning protection systems and, more particularly, to a lightning protection system for advanced (boron or graphite epoxy) composite aircraft structures. A study of lightning and static electricity related problems with respect to the use of advanced composite structures in aircraft such as boron and graphite epoxy composite structures indicates that lightning protection methods are necessary for such types of advanced structures so that they may be efficiently utilized in various regions of the outer surface of the aircraft. Present and contemplated protection systems utilize metal conductors to shunt lightning currents around the resistive composite materials. Such metal conductors may comprise foils, straps, screens, or flame-sprayed material. In such approaches the current is generally shared by the composite with possible consequent result in damage to the composite structure of the aircraft.

Heretofore, the patent literature, e.g., U.S. Pat. No. 4,186,237, issued Jan. 29, 1980, has been illustrative of the utilization of a material laid over thermally and electrically conductive layers which is capable of releasing a cloud of ionized and ionizable particles to spread the area affected by a lightning flash and to fan out the current path.

Further exemplary of the patent literature is U.S. Pat. No. 4,237,514, issued Dec. 2, 1980, which shows a lightning diverter strip for utilization on an aircraft component, the lightning strip having an epoxy coating or layer of uniformly dispersed powdered metallic particles.

It is an object of the present invention to provide a lightning protection system for the external surface of composite materials used in external surface portions of an aircraft.

A full understanding of the invention, and of its further objects and advantages and the several unique aspects thereof, will be had from the following description when taken in conjunction with the accompanying drawing in which:

FIG. 1 is a cross section through a preferred embodiment of the present invention illustrative of lightning attachment point, and current channnel formation shown diverted around the lightning protection structure provided for the advanced composite structure component of an aircraft.

Turning now to FIG. 1, an exposed surface portion of an aircraft needing lightning protection is comprised of an advanced composite material and shown as a graphite epoxy composite skin panel member 15. A supporting aircraft structural component for skin panel member 15 is shown as metal support member 16 providing a reference potential point. A layer of dielectric material, e.g., Kapton (a polyimide), is shown having the lower surface thereof applied to the outer surface of composite skin panel member 15 to be protected from lightning. The upper surface of dielectric layer 16 includes a binder material 10 carrying a conductive metal powder of finely divided particles uniformly deposited along the upper surface area of dielectric layer 16. Binder 10 carrying finely divided metal particles may comprise an epoxy binder and conductive metal powder of finely divided aluminum as shown, for example, in hereinbefore-mentioned U.S. Pat. No. 4,237,514.

Dielectric layer 16 may comprise the hereinbefore-mentioned material which has a high characteristic voltage breakdown or other dielectric material having a high dielectric strength with respect to voltage breakdown; and, the thickness of dielectric layer 16 should be between 0.01 inches and 0.1 inches, the thickness of dielectric layer 16 being dependent upon the distance of dielectric protective layer 16 and reference potential as provided by adjacent metal support structure such as 16. The further that dielectric layer 16 is located from the ground reference member, the greater the thickness being required for dielectric layer 16.

A lightning strike attachment point 12 is seen in the embodiment of the present invention shown in FIG. 1 to result in a current channel 14 being formed between lightning attachment point 12 and metal support structure member 16, the current path 14 being diverted around composite structure member 15 by the action of the uniformly distributed metal particles in a supporting binder shown at 10 above dielectric layer 16. The present lightning protection system for external surface composite material of an aircraft should be utilized to provide lightning protection to composite material members located where either a direct stroke or a swept stroke has an increased likelihood of occurrence due to particular location on the aircraft.

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4522889 *Jan 12, 1984Jun 11, 1985Bayer AktiengesellschaftLightning protection composite material
US4755904 *Jun 6, 1986Jul 5, 1988The Boeing CompanyLightning protection system for conductive composite material structure
US4824713 *Mar 10, 1988Apr 25, 1989The Boeing CompanyLightning protected structural surface
US4892626 *Jan 21, 1988Jan 9, 1990Boeing CompanyMethod for plating one side of a woven fabric sheet
US5089325 *Feb 4, 1991Feb 18, 1992The Boeing CompanyPartially coated fabric sheet
US5869814 *Aug 22, 1996Feb 9, 1999The Boeing CompanyPost-weld annealing of thermoplastic welds
US5916469 *Jul 29, 1996Jun 29, 1999The Boeing CompanySusceptor integration into reinforced thermoplastic composites
US5925277 *Apr 3, 1998Jul 20, 1999The Boeing CompanyAnnealed thermoplastic weld
US5935475 *Apr 3, 1998Aug 10, 1999The Boeing CompanySusceptor integration into reinforced thermoplastic composites
US7014915 *Aug 20, 2002Mar 21, 2006The Boeing CompanyControlled binary macrosegregated powder particles, their uses, and preparation methods therefor
US7120004 *Aug 17, 2004Oct 10, 2006Hall Allen LCurrent diverter strip and methods
US7236343Jan 5, 2005Jun 26, 2007The Boeing CompanyMethod and system for lightning current conduction protection using foil bonded strips
US7355832 *Jul 9, 2004Apr 8, 2008General Electric CompanyMethods and arrangements for reducing partial discharges on printed circuit boards
US7938625 *Jan 12, 2005May 10, 2011Lm Glasfiber A/SBlade for a wind energy plant comprising segmented conductor means for conducting lightning
US7972983Nov 2, 2004Jul 5, 2011Hexcel CorporationInterlock double weave fabric and methods of making and using the same
US8413929 *Mar 23, 2009Apr 9, 2013Mitsubishi Heavy Industries, Ltd.Aircraft assembly
US8503153Apr 15, 2010Aug 6, 20133M Innovative Properties CompanyLightning protection sheet with patterned discriminator
US8715824 *Sep 15, 2004May 6, 2014The Boeing CompanyApplique
US8760838May 6, 2013Jun 24, 20143M Innovative Properties CompanyLightning protection sheet with patterned discriminator
US8922970Apr 15, 2010Dec 30, 20143M Innovative Properties CompanyLightning protection sheet with patterned conductor
US8998124 *Mar 7, 2013Apr 7, 2015Bell Helicopter Textron Inc.Aircraft with electrically conductive nanocoating
US20040038066 *Aug 20, 2002Feb 26, 2004Cordaro James F.Controlled binary macrosegregated powder particles, their uses, and preparation methods therefor
US20050041362 *Aug 17, 2004Feb 24, 2005Hall Allen L.Current diverter strip and methods
US20050098224 *Nov 2, 2004May 12, 2005Don TaylorInterlock double weave fabric and methods of making and using the same
US20050181203 *Sep 15, 2004Aug 18, 2005Rawlings Diane C.Applique
US20060007624 *Jul 9, 2004Jan 12, 2006Sundaram Senthil KMethods and arrangements for reducing partial discharges on printed circuit boards
US20060146473 *Jan 5, 2005Jul 6, 2006Heidlebaugh Diane LMethod and system for lightning current conduction protection using foil bonded strips
US20070253827 *Jan 12, 2005Nov 1, 2007Morten DahlBlade for a Wind Energy Plant Comprising Segmented Conductor Means for Conducting Lightning
US20100224724 *Mar 23, 2009Sep 9, 2010Yuichiro KaminoAircraft assembly
US20100263898 *Apr 15, 2010Oct 21, 20103M Innovative Properties CompanyLightning protection sheet with patterned conductor
US20100264665 *Oct 21, 20103M Innovative Properties CompanyLightning protection sheet with patterned discriminator
US20140252164 *Mar 7, 2013Sep 11, 2014Bell Helicopter Textron Inc.Aircraft with Electrically Conductive Nanocoating
US20150102160 *Oct 11, 2013Apr 16, 2015Mitsubishi Aircraft CorporationLightning protection fastener and aircraft
CN101855132B *Mar 23, 2009Sep 2, 2015三菱重工业株式会社航空器组装品
CN102545063A *Feb 23, 2012Jul 4, 2012西安爱邦电磁技术有限责任公司Sectional type lightning guide strip and manufacturing method thereof
CN102545063BFeb 23, 2012Jan 9, 2013西安爱邦电磁技术有限责任公司Sectional type lightning guide strip and manufacturing method thereof
DE102008035917A1 *Aug 1, 2008Feb 4, 2010Eads Deutschland GmbhBlitzschutz von Radomen und Sende-/Empfangsvorrichtungen
DE102008035917B4 *Aug 1, 2008Jun 17, 2010Eads Deutschland GmbhBlitzschutz von Radomen und Sende-/Empfangsvorrichtungen
EP0207825A1 *May 26, 1986Jan 7, 1987AEROSPATIALE Société Nationale IndustrielleLightning protection material
EP0227122A2 *Aug 7, 1986Jul 1, 1987The Boeing CompanyLightning protection apparatus for an exterior surface
EP0707145A1 *Oct 11, 1995Apr 17, 1996AUTOFLUG ENERGIETECHNIK GmbH + CO.Lightning protection for wind turbine
EP1980647A1Sep 21, 2007Oct 15, 2008Hexcel Composites LimitedCurable resin films
EP2650210A1 *Apr 15, 2010Oct 16, 20133M Innovative Properties Company of 3M CenterLightning protection sheet with patterned discriminator
WO2006086083A2 *Dec 21, 2005Aug 17, 2006Boeing CoMethod and system for lightning current conduction protection using foil bonded strips
WO2010121058A2 *Apr 15, 2010Oct 21, 20103M Innovative Properties CompanyLightning protection sheet with patterned discriminator
Classifications
U.S. Classification361/117, 361/218
International ClassificationB64D45/02, H02G13/00
Cooperative ClassificationH02G13/80, H02G13/00, B64D45/02
European ClassificationB64D45/02, H02G13/00
Legal Events
DateCodeEventDescription
May 6, 1981ASAssignment
Owner name: BOEING COMPANY, THE SEATTLE, WASH. A CORP. OF DE.
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:KING CHARLES H.;REEL/FRAME:003887/0860
Effective date: 19810504
Owner name: BOEING COMPANY, THE, WASHINGTON
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:KING CHARLES H.;REEL/FRAME:003887/0860
Effective date: 19810504
Mar 23, 1987FPAYFee payment
Year of fee payment: 4
Sep 3, 1991REMIMaintenance fee reminder mailed
Feb 2, 1992LAPSLapse for failure to pay maintenance fees
Apr 7, 1992FPExpired due to failure to pay maintenance fee
Effective date: 19920131